382 THOMAS H. MONTGOMERY. 



PLATE II. 



FIGS. 12, 13. Penultimate spermatogonia in divis-'on. 



FIGS. 14-16. Rods of penultimate spermatogonia. 



FIG. 17. Quadrinucleate ultimate spermatogonium. 



FIG. 1 8. Binucleate ultimate spermatogonium. 



FIGS. 19, 20'. Ultimate spermatogonia. 



FIGS. 21-24. Rods of ultimate spermatogonia. 



FIG. 25. An incipient Sertoli cell (A) next to two ultimate spermatogonia 

 (B, C), and to a degenerate Sertoli cell (>). The inner margin of the wall of the 

 seminiferous tubule is at the left. 



